JP2002032941A - Head position adjusting method and recording/ reproducing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a head position adjusting method and a recording/ reproducing device in which the relative position between an optical head and a magnetic head can be easily and reliably adjusted. SOLUTION: An information recording medium 10 is irradiated with a laser beam for adjusting the head position from the optical head 12 while relatively moving the magnetic head 14 with respect to the optical head 12 by using a head position adjusting device 15. At this time, the position of an objective lens 21 is shifted from the position at the time of recording to reproducing operation to the direction of optical axis by using a movement device 22 to form a light spot having a spot area larger than that at the time of recording or reproduction on an information recording medium. The reproduction signal is detected from the information recording medium by a signal detecting system 13, and when the intensity of the reproduction signal becomes maximum, a controller 16 controls a head position adjusting device 15 to fix the position of the magnetic head 14. The position is fixed at the optimum relative position for the optical head 12 and the magnetic head 14.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a head position adjusting method for an optical head and a magnetic head and a recording / reproducing apparatus, and more particularly, to an optical head capable of forming a minute light spot on an information recording medium and a minute magnetic field application area. TECHNICAL FIELD The present invention relates to a head position adjusting method and a recording / reproducing apparatus for a magnetic head capable of forming a magnetic head.

[0002]

2. Description of the Related Art A magneto-optical recording medium such as a magneto-optical disk is known as an external memory of a computer or the like. Magneto-optical recording media are frequently used as recording media in the multimedia era because information can be rewritten and large-capacity data such as moving images and audio can be handled.

An apparatus for recording and reproducing such a magneto-optical recording medium usually includes an optical head and a magnetic head. The optical head and the magnetic head are coaxially arranged so as to sandwich the magneto-optical recording medium, and are incorporated so as to move in conjunction with each other during recording and reproduction. That is, when the optical head moves on one surface of the magneto-optical recording medium following a recording track, the magnetic head moves on the other surface of the medium accordingly.

At present, the optical head is equipped with a laser light source having an oscillation wavelength of about 650 nm and an objective lens having a numerical aperture of 0.6, and a light spot diameter (light irradiation area) formed on a medium by the optical head. Is about 1 μm. On the other hand, the magnetic field application region formed on the medium by the magnetic head is about 10 μm, which is wider than the light spot.

[0005]

In recent years, in order to increase the capacity of a magneto-optical recording medium, a method of recording information at a high density by miniaturizing a recording mark (recording magnetic domain) has been proposed. To miniaturize the recording mark, it is only necessary to miniaturize the light spot, and in order to realize this, the technology of practically using a blue laser with a short wavelength and increasing the NA of the objective lens is being promoted. Further, a method has been proposed in which a magnetic field application area in the track direction is narrowed by using a floating magnetic head as used in a magnetic disk, and the mark length of a recording mark is shortened to increase the recording density in the track direction. ing.

However, when the light spot formed on the magneto-optical recording medium and the magnetic field application region are both miniaturized, the relative position between the magnetic head and the optical head is slightly shifted.
The position of the light spot formed on the medium does not match the position of the magnetic field application region, and information cannot be recorded or reproduced. Therefore, it is necessary to adjust the relative position between the optical head and the magnetic head with higher accuracy than in the past, and it is considered that their alignment becomes more difficult. If the relative positions of the optical head and the magnetic head are incorrectly aligned, the position of the light spot does not match the position of the magnetic field application area, so that the overwriting may occur during overwriting or the desired information may be reproduced during information reproduction. There is a possibility that the recording mark cannot be reproduced.

The present invention has been made in view of such circumstances, and an object of the present invention is to reduce both a light spot formed on a medium by an optical head and a magnetic field application region formed by a magnetic head. It is therefore an object of the present invention to provide a head position adjusting method and a recording / reproducing apparatus capable of easily and surely adjusting the relative position between the optical head and the magnetic head even in the case of the above.

[0008]

According to a first aspect of the present invention, there is provided a recording / reproducing apparatus including an optical head for irradiating an information recording medium with a laser beam and a magnetic head. the head position adjusting method for adjusting the position, as large light spot S _L of the spot area is formed on the information recording medium than the light spot formed on the information recording medium during recording or reproducing irradiating a laser beam for position adjustment, and detects a reproduction signal from the information recording medium by the light spot S _L, to adjust the relative position of the optical head and the magnetic head based on the detected reproduction signal A featured head position adjusting method is provided.

According to such a head position adjusting method, even if the light spot formed on the information recording medium at the time of information recording / reproduction is miniaturized and the magnetic field application region is miniaturized for the purpose of high density, for example, the micro light It is possible to easily detect the relative position of the optical head and the magnetic head for forming the spot and the minute magnetic field application region, respectively, and to match the position of the light spot with the position of the magnetic field application region. And the position of the magnetic head can be easily adjusted. Below,
A description will be given based on the principle of the head position adjusting method of the present invention.

First, an optical head for forming a light spot on an information recording medium and a magnetic head for forming a magnetic field application area are arranged so as to be substantially coaxial with the information recording medium therebetween. Then, such a large light spot S _L of spot area than the light spot formed on the information recording medium during or at the time of reproducing recorded is formed on the information recording medium, irradiating the laser beam for position adjustment according to the method described below I do. By moving the magnetic head relatively to the optical head by slightly moving the magnetic head in the track direction or the track width direction, a reproduction signal is detected from the information recording medium using the light spot _SL having a large spot area. By increasing the spot area of the light spot, the area overlapping with the magnetic field application area formed by the magnetic head is increased. That is, the detection range of the reproduction signal is widened. Then, while moving the magnetic head relative to the optical head, the position of the magnetic head is fixed when the detected reproduction signal intensity becomes maximum. As a result, the optical head and the magnetic head are arranged at desired positions. That is, the light spot formed on the medium by the optical head coincides with the magnetic field application region formed on the medium by the magnetic head. In this state, if recording or reproduction is performed by returning the size of the light spot by the optical head to a predetermined size to be used at the time of recording / reproducing, information in a state where the light spot and the magnetic field application region are accurately matched is obtained. Can be recorded or reproduced. As described above, in the present invention, only when adjusting the head position, the information recording medium is irradiated with the laser beam for position adjustment and the reproduction signal is detected using the light spot having a large spot area. The relative position of the magnetic head can be detected very easily.

According to the present invention, for example, before recording / reproducing, recording is performed on a recording track for trial writing at a specific frequency, and then information recorded on the recording track for trial writing is written in accordance with the above-described head position adjusting method. And the relative position between the optical head and the magnetic head can be optimized while detecting the reproduced signal. When recording is performed in a state where the relative positions of the optical head and the magnetic head are optimized, it is possible to prevent the unerased portion from being left in overwriting. Also, at the time of reproduction, information can be reproduced by reliably transferring a desired recording mark to the reproduction layer.

For example, the head position adjusting method of the present invention
By using the optical head and the magnetic head in the recording / reproducing apparatus, the optical head and the magnetic head can be easily and reliably fixed at the optimum relative position.

In the present invention, as a first method for forming a light spot having a larger spot area on an information recording medium than at the time of recording or reproduction, for example, the focal position of an objective lens is determined from the position at the time of recording or reproduction. A shifting method can be used. That is, this method is to shift the focal position of the objective lens, which is adjusted on the recording film surface of the information recording medium for recording or reproduction, from the recording film surface when performing relative positioning of the head. At the time of recording and reproduction, a light spot of just focus narrowed down to the diffraction limit is usually formed on the information recording medium. When performing relative positioning between the optical head and the magnetic head,
The light spot formed on the information recording medium can be shifted from the just-focused state to be out-of-focus. Thereby, the spot area of the light spot can be made larger than at the time of recording or reproduction. Out-focus, for example, moving the position of the objective lens with respect to the information recording medium in the optical axis direction of the laser beam or the optical axis direction of the objective lens, or between the objective lens and the medium, that is, of the converged light converged by the objective lens It is possible by interposing an optical element such as a knife edge or a lens on the optical path.

In the present invention, as a second method for forming a light spot having a larger spot area than a light spot formed on an information recording medium at the time of recording or reproduction, the light spot is separated into two or more light spots. A method can be used. In order to separate the light spot into two or more light spots, for example, a laser beam may be split into two or more diffracted light rays using a diffraction grating or a hologram element and irradiated onto a medium. If such a method is used, for example, 0
Three light spots of the first-order diffracted light and ± first-order diffracted light can be formed. In this case, a detector for detecting a reproduction signal corresponding to each light spot can be provided. The magnetic head is divided into the 0th-order diffracted light and ± 1st-order diffracted light.
When the light spot is moved in the direction in which the two light spots are arranged, a reproduced signal can be detected from any one of the detectors provided corresponding to those light spots. Then, if the magnetic head is moved so that the reproduction signal is detected from the detector corresponding to the light spot of the zero-order diffracted light, the relative positioning between the optical head and the magnetic head can be performed. At the time of recording / reproducing, the light spot separated into two or more may be returned to one, or the light spot separated into two or more may be used as it is. For example, if the light spot is 0
When the light is separated into three light spots of the first-order diffracted light and ± first-order diffracted light, for example, the principle of a three-spot signal detection method that detects a tracking signal using three light spots, which is a kind of tracking signal detection method, is described. The light spot of the 0th-order diffracted light may be used for recording and reproduction, and the light spot of the ± 1st-order diffracted light may be used for tracking.

As a third method for forming a light spot having a larger spot area than at the time of recording or reproduction,
A method of dispersing a light spot can also be used. Here, the term “dispersion” means a state in which two or more light spots overlap each other. By dispersing the light spot, the spot area of the light spot formed on the information recording medium also increases. In order to disperse the light spot, a diffraction grating or a hologram element can be used as in the case of separating the light spot. In this case, for example, the diffraction angle of the diffraction grating may be made narrower than when the light spot is separated.

The light spot formed on the information recording medium at the time of head position adjustment according to the present invention preferably has a shape such that the length in the direction parallel to the track is longer than the length in the direction perpendicular to the track. For example, a magnetic head used in a hard disk is in a direction perpendicular to a track (track width direction).
Long in the direction parallel to the track (track direction). That is, the magnetic field application region formed on the medium by the magnetic head is long in the track width direction and short in the track direction. Therefore, it is difficult to match the magnetic field application region with the light spot in the track direction. By dispersing the light spot in a direction parallel to the track, the area where the magnetic field application area and the light spot overlap increases, so that the position where the magnetic field application area coincides with the light spot can be easily detected, and the optical head and the magnetic head can be easily detected. Adjustment of the relative position with the head becomes easy.

In order to make the light spot in a shape in which the length in the direction parallel to the track is longer than the length in the direction perpendicular to the track, for example, when dispersing the above-mentioned light spot, The diffraction grating or the hologram element may be arranged so as to be dispersed. When the light spot is separated into two or more, the diffraction grating or the hologram element may be arranged so that the light spots are arranged in the track direction. Also, by tilting the information recording medium or tilting the converging objective lens, light is obliquely incident on the surface of the information recording medium, and the length of the medium in the track direction is equal to the length of the track width direction. A longer elliptical light spot may be used. Also, by making the laser light incident on the objective lens oblique to the optical axis of the lens, the convergent light emitted from the objective lens can be made oblique to the medium surface. An elliptical light spot whose length in the track direction is longer than the length in the track width direction can be formed.

In the present invention, when adjusting the relative position between the optical head and the magnetic head, it is preferable that the power of the laser beam for position adjustment applied to the information recording medium is higher than that at the time of information reproduction. The reason will be described below. In the following description, a case of a magneto-optical recording medium having a reproducing layer will be described.

Normally, in reproducing a magneto-optical recording medium having a reproducing layer, a laser beam is condensed and irradiated on the magneto-optical recording medium to form a light spot. A high-temperature region based on the light intensity distribution of the laser light is formed in the light spot, and the reproducing layer in the high-temperature region has a reduced coercive force. By applying a reproducing magnetic field to such a high-temperature region, the recording magnetic domains of the recording layer are magnetically transferred to the reproducing layer through the high-temperature region. By irradiating the information recording medium with laser light for position adjustment and making the spot area of the light spot larger than when reproducing information, the density of light in the spot decreases and the heat distribution formed in the spot also decreases. It becomes gentle. That is, the temperature of the high-temperature area in the light spot is lower than that of the light spot at the time of information reproduction, and the temperature difference between the high-temperature area and the low-temperature area is smaller. When the laser power is increased in a state where the light spot is enlarged and the heat distribution in the light spot is gentle, the entire light spot is uniformly heated. Therefore, the high-temperature region of the reproducing layer, that is, the transfer region where the recording magnetic domain of the recording layer is transferred is also widened,
Reproduction signal detection becomes easier. As a result, the position of the magnetic head with respect to the optical head can be easily detected, and the position adjustment between the optical head and the magnetic head is further facilitated.
By the way, even if the laser power is increased while the light spot is miniaturized, the high-temperature region formed in the reproducing layer can be widened. Therefore, it is considered that the transfer area can be enlarged. However, in this case, the temperature at the center of the spot is significantly increased, and the recording mark formed on the recording layer is destroyed. Therefore, as a method of enlarging the transfer area, a method of increasing the laser power while the light spot is large is an effective method.

In the present invention, for example, a magneto-optical recording medium having a reproducing layer can be used as the information recording medium. In this case, at the time of head position adjustment between the optical head and the magnetic head, a magnetic spot is applied to a predetermined position of the magneto-optical recording medium by the magnetic head, and the optical head has a light spot having a larger spot area than at the time of recording / reproduction. And a magneto-optical signal may be detected from the magneto-optical recording medium. Further, as the information recording medium, for example, a heat-assisted magnetic recording medium that records or reproduces information while applying heat during recording or reproduction can be used. In this case, a light spot having a larger spot area than at the time of recording / reproducing may be formed at a predetermined position on the magnetic recording medium by the optical head, and the magnetic signal may be detected from the magnetic recording medium by the magnetic head.

According to a second aspect of the present invention, in a recording / reproducing apparatus for an information recording medium, a light source for generating a laser beam, an optical head for irradiating the information recording medium with a laser beam, A magnetic head for applying a magnetic field;
Adjusting means for adjusting a spot area of a light spot formed on an information recording medium by the optical head; a head position adjusting device for adjusting a relative position between the optical head and the magnetic head; and a reproduction signal from the information recording medium. And a control device for controlling the head position adjusting device based on the reproduction signal detected by the signal detection device.

In the recording / reproducing apparatus according to the present invention, the adjusting means adjusts the spot diameter or the spot shape so that the spot area of the light spot formed on the information recording medium is larger than, for example, during recording or reproduction. be able to. Then, while the optical head and the magnetic head are relatively moved by the head position adjusting device, the reproduced signal is detected by the signal detecting device, and when the reproduced signal reaches the maximum, the control device controls the head position adjusting device. The relative position between the optical head and the magnetic head can be fixed. Thereby, the optical head and the magnetic head can be fixed at the optimum relative position.

When the information recording medium to be recorded / reproduced by the recording / reproducing apparatus of the present invention is a magneto-optical recording medium, the signal detecting device detects a signal for detecting a magneto-optical signal from the information recording medium through an optical head. It can be configured as a device. When the information recording medium to be recorded / reproduced by the recording / reproducing device is a magnetic recording medium, it can be configured as a signal detection device for detecting a magnetic signal from the information recording medium through a magnetic head.

In the recording / reproducing apparatus of the present invention, the adjusting means can be constituted by using, for example, a diffraction grating or a hologram element. Such a diffraction grating or hologram element can form two or more light spots on an information recording medium by adjusting the grating interval so as to separate laser light into two or more diffraction lights, for example.
Further, by adjusting the lattice spacing so that the diffraction angle becomes narrower than in the case where the light spots are separated, the laser light can be dispersed, and two or more light spots are superimposed on the information recording medium. Such a light irradiation region can be formed.

The adjusting means of the recording / reproducing apparatus of the present invention may be, for example, a galvano mirror for adjusting the angle of the laser beam incident on the objective lens, or the information recording medium whose surface is in the track direction with respect to the laser optical axis. And a tilt stage for tilting and supporting the information recording medium so as to be inclined. The adjusting means having such a configuration can form a light spot whose length in the track direction is longer than that in the track width direction on the information recording medium.

The optical head of the recording / reproducing apparatus of the present invention may include, for example, an objective lens for converging a laser beam on an information recording medium. In this case, the adjusting means can be configured using a moving device for moving the focal position of the objective lens in the optical axis direction. When adjusting the head position, the moving device can shift (out-focus) the focal position of the objective lens so that the spot area becomes larger than during recording or reproduction. Thus, at the time of head position adjustment, a light spot having a larger spot area than at the time of recording or reproduction can be formed on the information recording medium.

In the recording / reproducing apparatus of the present invention, for example, a laser light source having an oscillation wavelength of 400 nm to 700 nm can be used as a laser light source that can be mounted on the optical head, and a minute light spot can be formed. A laser light source having a possible oscillation wavelength of 400 nm to 650 nm is preferable. Further, as the objective lens, an objective lens having a numerical aperture of 0.6 to 1.0 can be used, and an objective lens having a numerical aperture of 0.6 to 0.9 is particularly preferable in that a minute light spot can be formed. It is.

[0028]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a head position adjusting method and a recording / reproducing apparatus according to the present invention will be specifically described below, but the present invention is not limited thereto.

[0029]

EXAMPLE A magneto-optical recording medium having a laminated structure as shown in FIG. 2 was manufactured as an example of an information recording medium used in a recording / reproducing apparatus according to the present invention. The magneto-optical recording medium 10
As shown in FIG. 2, it has a structure in which a first dielectric layer 2, a reproducing layer 3, a second dielectric layer 4, a recording layer 5, a third dielectric layer 6, and a reflective layer 7 are sequentially laminated on a substrate 1. .

In FIG. 2, a land / groove type polycarbonate substrate capable of recording information in both grooves (grooves) and between grooves (lands) was used as the substrate 1. The first dielectric layer 2 was made of SiN and had a thickness of 60 nm. The reproducing layer 3 is a layer to which magnetic domains are transferred from the recording layer at the time of reproducing information, and is formed using GdFeCo having perpendicular magnetization. The thickness of the reproducing layer 3 was 20 nm. The second dielectric layer 4 was made of SiN and had a thickness of 5 nm. The recording layer 5 is a layer for recording information in a magnetized state, and is made of TbFeCo having perpendicular magnetization. The thickness of the recording layer 5 was 50 nm. The third dielectric layer 6 includes SiN
And the film thickness was set to 20 nm. The reflective layer 7 was made of an Al alloy and had a thickness of 30 nm. Each of these layers 2 to 7 was formed on the substrate 1 by using a magnetron sputtering apparatus (not shown), thereby producing a magneto-optical recording medium 10 having a laminated structure as shown in FIG.

Next, a recording / reproducing apparatus according to the present invention will be described. FIG. 1 shows a schematic configuration of an optical system of the recording / reproducing apparatus. The recording / reproducing device 100 is a device for recording / reproducing the magneto-optical recording medium 10. The recording / reproducing device 100
It mainly includes a laser light source 11, an optical head 12, a signal detection system 13, a magnetic head 14, a magnetic head position adjusting device (actuator) 15, and a control device 16. The magneto-optical recording medium 10 is loaded in the recording / reproducing apparatus 100 such that a laser beam enters from the substrate 1 side.

The laser light source 11 is used for the magneto-optical recording medium 10.
And a laser light source having an oscillation wavelength of 680 nm. The laser light emitted from the laser light source 11 is shaped into parallel light having a circular cross section by a collimator lens 17 and polarized by a polarizer 18 so as to pass through a beam splitter 19. And enters the objective lens 21 of the optical head 12.

The optical head 12 includes an objective lens 21 and a moving device 22. The objective lens 21 is an objective lens having a numerical aperture of 0.55, and can focus laser light from the laser light source 11 on the magneto-optical recording medium 10. The diameter of a light spot formed on the magneto-optical recording medium 10 by the laser light source 11 and the objective lens 21 is about 1 μm. The moving device 22 is a device for moving the objective lens 21 in the direction of the optical axis, and is vertically moved by a magnetic holder (not shown) holding the objective lens 21 and a magnetic coil provided around the magnetic holder. And a linear actuator 23 to be driven.

The magnetic head 14 is provided at a position facing the optical head 12 with the magneto-optical recording medium 10 interposed therebetween.
An alternating magnetic field can be applied to the magneto-optical recording medium 10 when recording and reproducing information. Also, the magnetic head 14
Means that the length in the track direction on the magneto-optical recording medium 10 is 15
A magnetic field application region having a length of 0 μm and a length in the track width direction of 200 μm can be formed.

The signal detection system 13 includes components such as a detector for detecting a magneto-optical signal contained in the reflected light from the magneto-optical recording medium 10 and various optical elements.

The magnetic head position adjusting device 15 can position the magnetic head 14 at a predetermined position on the magneto-optical recording medium and can finely adjust the relative position of the magnetic head 14 with respect to the optical head 12. Control device 1
6 controls the magnetic head position adjusting device 15 based on the magneto-optical reproduction signal detected by the signal detection system,
The relative position of the magnetic head 14 with respect to the position can be adjusted to the optimum position. Thus, the position of the light spot formed on the medium 10 by the optical head 12 and the position of the magnetic field application region formed on the medium by the magnetic head 14 can be accurately matched.

In the recording / reproducing apparatus 100 having the above configuration, when recording or reproducing information, the laser light source 11
The position of the objective lens 21 is finely adjusted by the moving device 22 so that the laser beam emitted from the focusing device is focused on the recording layer or the reproducing layer of the magneto-optical recording medium 10. Thereby, the laser beam is narrowed down to the diffraction limit at the position of the recording layer or the reproducing layer of the magneto-optical recording medium 10 (just focus state), and the recording layer or the reproducing layer of the magneto-optical recording medium has a light spot diameter of 1 μm. A light spot is formed.

When the relative positions of the optical head 12 and the magnetic head 14 are aligned, the optical head 12 and the magnetic head 1 are aligned.
Reference numeral 4 is positioned substantially coaxially at a position facing the optical magnetic recording medium. Then, the objective lens 21 is moved in the optical axis direction by using the moving device 22 so that the light spot formed on the magneto-optical recording medium is larger than that at the time of recording or at the time of reproduction, so as to be in an out-of-focus state.

While the magnetic head 14 is relatively moved with respect to the optical head 14 by the magnetic head position adjusting device 15, a reproduced signal is detected from the signal detection system 13 using the out-of-focus laser light. Then, the control device 16 controls the magnetic head position adjusting device 15 so that the reproduced signal is maximized, and the magnetic head 14 is moved to the optical head 12.
Relative to. The control device 16 controls the magnetic head position adjusting device 15 to fix the position of the magnetic head 14 when the reproduction signal becomes maximum. Thereby, the relative position between the magnetic head 14 and the optical head 12 is optimized. That is, the position of the light spot formed on the medium by the optical head 12 exactly matches the position of the magnetic field application region formed on the medium by the magnetic head 14.

Next, using the recording / reproducing apparatus 100, continuous recording marks having a mark length of 0.5 μm were recorded on the magneto-optical recording medium 10 under the following recording conditions. The laser power during recording was 10 mW, and the linear velocity of the medium was 2.5 m /
s, the recording magnetic field strength is ± 200 Oe (about ± 15916 A /
m), and the recording magnetic field alternating frequency was 5 MHz.

Next, in order to align the optical head and the magnetic head, information is recorded on the magneto-optical recording medium by shifting the position of the objective lens by about 2 μm in the optical axis direction from the position at the time of information recording (or at the time of information reproduction). A light spot larger than the time (or at the time of information reproduction) was formed. That is, the focus position of the objective lens was shifted from above the recording layer (or the reproduction layer) to perform out-of-focus. The magnetic head 14 moves the magnetic head 14 relative to the optical head 12 while applying a reproducing magnetic field strength of ± 200 Oe (about ± 15916 A / m) and a reproducing magnetic field alternating frequency of 12.5 MHz. Detected.

When a reproduced signal of a continuous recording mark from the magneto-optical recording medium was observed with an oscilloscope, FIG.
Waveforms as shown in FIGS. FIG. 3 (A)
FIG. 3B shows the case where the relative position of the magnetic head to the optical head is 0 μm, FIG. 3B shows the case where the relative position is 0.3 μm, and FIG. Here, the relative position is the distance between the optical axis of the objective lens of the optical head and the central axis of the magnetic field generating section of the magnetic head. In the oscilloscope waveform shown in FIG. 3, the upper waveform is the waveform of the reproduction signal from the magneto-optical recording medium, and the lower waveform is the waveform of the reproducing magnetic field applied to the magneto-optical recording medium during reproduction. It is.

For comparison, a state where the focal position of the objective lens is on the reproduction layer (just focus state)
In the same manner as above, the reproducing magnetic field strength is ± 200 Oe with the magnetic head.
(Approximately ± 15916 A / m), reproducing magnetic field alternating frequency
The magnetic head was moved relative to the optical head while applying a reproducing magnetic field of 5 MHz, and a reproducing signal was detected. FIGS. 4A to 4C show the results of observation of a reproduction signal of a continuous recording mark from the magneto-optical recording medium in the just-focus state using an oscilloscope.

As can be seen from FIG. 3, by detecting the reproduction signal in the out-of-focus state, the reproduction signal could be detected even when the relative position between the optical head and the magnetic head reached 0.4 μm. On the other hand, as can be seen from FIG. 4, when the reproduced signal was detected in the just-focused state, it was difficult to detect the reproduced signal when the relative position between the optical head and the magnetic head became 0.3 μm.

FIG. 5 shows how the reproduction signal level changes with respect to the relative position between the optical head and the magnetic head in the just-focus state and the out-focus state. In FIG. 5, as the reproduced signal on the vertical axis, a value normalized by the reproduced signal intensity detected when the relative position between the optical head and the magnetic head is zero in the just-focused state is used. As can be seen from the figure, in the case of just focus, the reproduced signal sharply decreases as the relative position between the optical head and the magnetic head increases. On the other hand, in the case of out-of-focus, that is, when the light spot is enlarged, the reproduction signal can be detected even if the relative position becomes large. This means that the range in which the reproduction signal can be detected is wide, and that the optical head and the magnetic head can be easily aligned.

As described above, the recording / reproducing apparatus and the head position adjusting method according to the present invention have been specifically described with reference to the embodiments. However, the present invention is not limited thereto. For example,
As the optical head, an integrated optical head on which optical components such as a semiconductor laser, a photodetector, an objective lens, and a microprism are mounted may be used.

Further, as a recording / reproducing apparatus according to the present invention,
For example, a recording / reproducing device 600 having a schematic configuration as shown in FIG. 6 may be used. In FIG. 6, the tilt stage 61 tilts the magneto-optical recording medium so that the optical axis of the laser beam is oblique to the track direction when adjusting the relative position of the optical head 12 and the magnetic head 14. And can be rotatably supported. As a result, when adjusting the relative position of the head, an elliptical light spot having the major axis in the track direction is formed on the magneto-optical recording medium, and the area in which the reproduced signal can be detected can be widened.

The galvanomirror 62 adjusts the relative position of the head so that the optical axis of the laser beam incident on the objective lens 21 is oblique to the optical axis of the objective lens 21. The angle of the laser light to be incident can be adjusted. It is desirable that the galvanomirror 62 be disposed such that the optical axis of the convergent light is oblique to the track direction of the medium. Such a galvanometer mirror 6
The laser light whose incident angle on the objective lens 21 is adjusted by 2 is converged by the objective lens 21 and then obliquely enters the medium surface. As a result, the light spot formed on the medium has an elliptical shape whose major axis is the track direction. Therefore, the area where the reproduction signal is detected increases.

Also, a diffraction grating (or hologram element)
The 63 can irradiate the laser beam emitted from the semiconductor laser 11 by separating or dispersing it on a medium when adjusting the relative position of the head. This makes it possible to form, on the medium, a light irradiation area in which two or more separated light spots or two or more light spots are superimposed.

The recording / reproducing apparatus 600 shown in FIG. 6 has a configuration in which the tilt stage 61, the galvanometer mirror 62, and the diffraction grating (or hologram element) 63 are all provided.
At least one of them may be provided.

In place of the magneto-optical recording medium, an in-plane magnetic recording type magnetic recording medium or a perpendicular magnetic recording type magnetic recording medium can be used. In this case, the optical head can be used for heating the medium, and the signal detection system can be changed to a signal detection system used in a magnetic recording device so that a reproduction signal can be detected through the magnetic head. As the magnetic head, for example, an inductive head such as a ferrite head, a MIG (Metal In Gap) head, a thin film head, or an MR inductive composite head in which such an inductive head and an MR (Magneto-Resistive) head are integrated is used. be able to. In addition, GMR (Giant Magnet
An o-Resistive) head may be used.

[0052]

According to the present invention, when the relative position between the optical head and the magnetic head is adjusted, the reproduction signal is detected in a state where the spot area of the light spot is larger than that during recording or reproduction. The read signal can be easily detected even if the relative position between the magnetic head and the magnetic head is large,
The alignment between the optical head and the magnetic head can be easily performed.

Further, the recording / reproducing apparatus of the present invention
Since the relative position of the optical head capable of forming a minute light spot on the information recording medium and the magnetic head capable of forming the minute magnetic field application region can be easily and reliably adjusted to the optimum position, the information can be easily recorded and reproduced. The minute light spot formed on the recording medium and the minute magnetic field application region can be matched with high accuracy. Therefore, at the time of information recording, it is possible to overwrite in a state where the minute light spot and the minute magnetic field application area are matched with high precision, and the unerased portion of the recording mark is prevented. Marks can be reliably reproduced.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an optical system of a recording / reproducing apparatus according to the present invention.

FIG. 2 is a schematic sectional view of a magneto-optical recording medium manufactured in an example.

3A and 3B are waveforms of a reproduction signal and a reproduction magnetic field by an oscilloscope in an out-of-focus state. FIG. 3A shows a case where a relative position between an optical head and a magnetic head is 0 μm, and FIG. The relative position of the head and the magnetic head is 0.3μ
FIG. 3C shows a case where the relative position between the optical head and the magnetic head is 0.4 μm.

4A and 4B are waveforms of a reproduction signal and a reproduction magnetic field by an oscilloscope in a just focus state, and FIG. 4A shows a case where a relative position between an optical head and a magnetic head is 0 μm;
FIG. 4B shows that the relative position between the optical head and the magnetic head is 0.3.
FIG. 4C shows the case where the relative position between the optical head and the magnetic head is 0.4 μm.

FIG. 5 is a graph showing a change in a reproduction signal level with respect to a relative position of an optical head and a magnetic head in an out-focus state and a just-focus state.

FIG. 6 is a schematic configuration diagram of a specific example different from FIG. 1 of the recording / reproducing apparatus according to the present invention.

[Explanation of symbols]

 Reference Signs List 1 substrate 2 first dielectric layer 3 reproducing layer 4 second dielectric layer 5 recording layer 6 third dielectric layer 7 reflection layer 10 magneto-optical recording medium 11 laser light source 12 optical head 13 signal detection system 14 magnetic head 15 magnetic head Position adjusting device 16 Control device 21 Objective lens 22 Moving device 61 Tilt stage 62 Galvano mirror 63 Diffraction grating or hologram element 100, 600 Recording / reproducing device

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G11B 5/02 G11B 5/02 S 11/10 502 11/10 502Z (72) Inventor: Imai Susumu, Ibaraki, Osaka 1-88, Ichi-Ushitora, Hitachi Maxell Co., Ltd. (72) Inventor Kazuko Inoue 1-1-88, Ushitora, Ibaraki-shi, Osaka In-house Hitachi Maxell Co., Ltd. 1-88 No. 1 F-term (reference) in Hitachi Maxell, Ltd. 5D075 AA03 CC11 CD10 CE01 CF06 5D091 AA08 CC24 DD03 HH20

Claims (24)

[Claims] 1. A head position adjusting method for adjusting a relative position between an optical head and a magnetic head in a recording / reproducing apparatus including an optical head for irradiating a laser beam onto an information recording medium and a magnetic head, comprising: than the light spot formed on the information recording medium by irradiating a laser beam for position adjustment so large light spot S _L of the spot area is formed on the information recording medium during or at the time of reproduction, the light spot S _L A read signal from the information recording medium, and adjusting a relative position between the optical head and the magnetic head based on the detected read signal. 2. The head position adjusting method according to claim 1, wherein the position adjusting laser beam has a laser power larger than a laser power of a laser beam applied to an information recording medium during reproduction. Wherein said optical head includes an objective lens for forming a light spot S _L, the position of the optical axis of the objective lens, the light spot by moving from the position at the time of recording or reproducing 3. The head position adjusting method according to claim 1, wherein an _SL is formed. 4. The head position adjustment according to claim 1, wherein the light spot _SL is formed by irradiating the laser light for position adjustment with a diffraction grating or a hologram element and irradiating the laser light. Method. Wherein said light spot S track direction parallel length of _L is such that is longer than the length in the direction perpendicular to the track, claim, characterized in that dispersing laser light 1 or 3. The head position adjusting method according to item 2. 6. The light spot _SL is composed of two or more light spots, and the two or more light spots are
3. The head position adjusting method according to claim 1, wherein the position adjusting laser beam is formed by separating the position adjusting laser beam into two or more diffracted lights by a diffraction grating or a hologram element. 7. The head position adjusting method according to claim 6, wherein the two or more light spots are formed side by side in a direction parallel to a track. 8. The optical spot S _L is a light spot shape longer than the length in the direction perpendicular to the track length in the direction parallel to the track, the light spot on the information recording medium surface 3. The head position adjusting method according to claim 1, wherein the head position adjusting method is performed by irradiating a laser beam for position adjustment obliquely. 9. The head position according to claim 8, wherein the surface of the information recording medium is inclined with respect to the laser optical axis so that the position adjusting laser beam is obliquely incident on the surface of the information recording medium. Adjustment method. 10. The optical head includes an objective lens for forming a light spot S _L, in order to incident laser beam for position adjustment obliquely with respect to the information recording medium surface, the optical axis of the objective lens 9. The head position adjusting method according to claim 8, wherein the objective lens is tilted so that the laser light axis and the laser beam intersect. 11. The head position adjusting method according to claim 1, wherein the information recording medium is a magnetic recording medium, and the reproduction signal is detected using the magnetic head. . 12. The head position adjusting device according to claim 1, wherein said information recording medium is a magneto-optical recording medium, and said reproducing signal is detected by using said optical head. Method. 13. The laser beam has a wavelength of 350 nm.
2. The method according to claim 1, wherein the wavelength is within a range of about 700 nm.
13. The head position adjusting method according to any one of claims 12 to 12. 14. A reproduction signal is detected while the optical head and the magnetic head are relatively moved, and the position of the optical head and the magnetic head is fixed when the signal intensity of the reproduction signal becomes maximum. The head position adjusting method according to any one of claims 1 to 13. 15. A recording / reproducing apparatus for an information recording medium, comprising: a light source for generating a laser beam; an optical head for irradiating the information recording medium with a laser beam; a magnetic head for applying a magnetic field to the information recording medium; Adjusting means for adjusting a spot area of a light spot formed on an information recording medium by an optical head; a head position adjusting device for adjusting a relative position between the optical head and the magnetic head; and a reproducing signal from the information recording medium. A recording / reproducing apparatus comprising: a signal detecting device for detecting; and a control device for controlling the head position adjusting device based on a reproduced signal detected by the signal detecting device. 16. The information recording medium is a magneto-optical recording medium, and the signal detecting device is a signal detecting device for detecting a magneto-optical signal from the information recording medium through the optical head. Item 16. The recording / reproducing device according to item 15. 17. The information recording medium is a magnetic recording medium, and the signal detection device is a signal detection device for detecting a magnetic signal from the information recording medium through the magnetic head. The recording / reproducing apparatus according to claim 1. 18. The recording / reproducing apparatus according to claim 15, wherein said adjusting means is a diffraction grating or a hologram element for dispersing a laser beam. 19. The adjusting means is a diffraction grating or a hologram element for separating a laser beam into two or more diffracted lights to form two or more light spots on an information recording medium. The recording / reproducing apparatus according to any one of claims 15 to 17. 20. A tilt stage for tilting and supporting an information recording medium such that a surface of the information recording medium is inclined with respect to a laser optical axis. 18. The recording and reproducing device according to any one of items 17. 21. The optical head according to claim 15, wherein the optical head includes an objective lens, and the adjusting means is a galvanomirror for adjusting an incident angle of the laser beam to the objective lens. A recording / reproducing apparatus according to claim 1. 22. The optical head according to claim 15, wherein the optical head has an objective lens, and the adjusting means is a moving device for moving the objective lens in an optical axis direction. The recording / reproducing apparatus according to claim 1. 23. The light source has an oscillation wavelength of 350 nm or more.
23. The recording / reproducing apparatus according to claim 15, wherein the recording / reproducing apparatus is a laser light source within a range of 700 nm. 24. A reproduction signal is detected by the signal detection device while relatively moving the positions of the optical head and the magnetic head by the head position adjustment device, and the signal intensity of the reproduction signal detected by the signal detection device is maximized. Wherein the control unit controls the head position adjusting device to fix the positions of the optical head and the magnetic head.
24. The recording and reproducing device according to any one of 23.